Spark plug



SPARK PLUG Filed Sept. 14, 1922 vwenhoz EM. 6180/ @Mozvw Patented den. 26D, 192.

EMIL GRAF, OF NEW YORK, N. Y.,

assreuon T RUDOLPH srmae your, a. Y.

SPARK PLUG.

Application filed September 14, 1922. Serial No. 588,136.'

To all whom it may concern:

Be it known that I, EMIL GRAF, a citizen of the Republic of Switzerland, residing at 'New York, county of New York, and State of New York, have invented certain new and useful Improvements in Spark Plugs,

of which the followingis a specification.

One of the principal objects of this in vention is to provide in a spark plug for circuit the plug when it is desired to test the firing of any particular cylinder or cylinders.

For the accomplishment of these and such further, objects as will hereinafter be apparent to those skilled in the art. to which 1 this appertains the invention consists in the construction, combination and arrangement of partsherein specifically described and illustrated in the accompanying drawings, wherein is shown a preferred embodiment ofthe invention, but it is tobe understood that changes, variations and modifications may be resorted to which fall within the scope of the claims hereunto appended.

In the drawings forming a portion of this specification Fig. 1 is a central sectional view through a spark plug embodying my invention.

Fig. 2 is a side view of the top portion of a plug showing a modified form ofthe means for opening or closing the observation openings.

Figs. 3 and 4 are views similar to Fig. 2 of a further modification of the opening or closing means.

Fig. 5 is a horizontal section on the line 5-5 of Fig. 1.

1 As shown in the drawings, afhol'lowmetal lic base 10 is provided with the threaded extremity 11 and the shoulder 12 adapted to be engaged with the engine cylinder in the usual and well known manner. Ihe base 10 carries the electrode 13 spaced from an electrode 14 to provide the usual spark gap, the electrode 14 being suitably secured within an insulating block 15, preferably of fibre, as by the bushing 16, which is forced upon. the electrode 14 and is screwed within one of the cup shaped recesses 17 formed in the extremities of the insulating block 15. Intermediate its ends the insulating block is provided with a projecting shoulder 18, which is adapted to be clamped between a shoulder 19 provided on the inner bore of the base 10, and the lower end of a top piece 20, which is screwed on the upperv end of the base, suitable gaskets 21 being provided to insure 'a tight joint.

It will be noted that the ends of the insulating block are equidistant from the shoulders 21 and the electrode 14 projects from the insulating block an equal distance I at each end, instead of passing entirely through the block, for a purpose which will hereinafter appear. j I

The top piece 20 is a hollow member having an annular shell like portion or casing 23 projecting upwardly from the enlarged shoulder 24 and which portion is preferably provided with any suitable number of apertures 25. The lower inner wall of the top piece may be provided with a shoulder 26 against which may beseated the lower end of 2. 5am '27 preferably of metal which isfrictionally engaged within the shell portion 23. i

v The sleeve 27 is preferably provided with a horizontally extending slot 50 having the recesses 51 at its ends, and the shell like portion 23 is provided with a resilient struck out tongue 52 having itsinner end turned inwardly as at 53 to engage within the recesses 51, the relative positions of the recesses and tongue being arranged to'hold the sleeve 27 with its apertures 27 a in or out of alignment with the apertures 25 and also to hold the sleeve longitudinally in the position of maximum efficiency of the air gap to be hereinafter described. The sleeve 27 is'also provided with a longitudinally extending slot, 55 which leads from one of the recesses 51 to the lower edge of the sleeve to permit longitudinal outward movement of the top piece.

The upper end of the sleeve 27 1s counterbored as at 28 to provide a shoulder in which is seated an upper insulating block 29 having a flanged shoulder 30 at its lower end about which the upper edge of the sleeve I 27 is spun to secure the block 29 and sleeve 27 together. A11 electrode 31 of suitable conducting material passes through the 'block 29 and its lower end terminates a short distance from the upper end of the electrode 14 to provide an intensifying gap which is located substantially in horizontalalignment with the apertures 25. The upper end of the electrode 31 is provided with the usual threaded end upon which the customary binding nut 32 is screwed.

The operation of the plug described above is as follows: In the ordinary operation of the plug the insulating block 29 and sleeve 27"will be turned to close the apertures as will be readily understood. If it is desired to observe the conditions under which the ignition system. is working, the block and sleeve are partially rotated to bring the apertures 27 into register with the apertures 25. As it will be'obvious that a spark may pass across the intensifying gap but its passage across the lower gap may be prevented by carbon deposit upon the terminals of the electrodes 13 and 14, the insusleeve 27.

through-the slot 55, when the parts arelatingblock 29 and sleeve 27 may be slid longitudinally to increase the gap between the electrodes 14 and 31, thereby causing the plug to be short circuited, the spark jumping across from the electrode 31 to the The Y tongue 52 may be slid moved longitudinally. If desired the struck out tongue 52, horizontal slot and recesses 51, may be dispensed with and the upper and lower parts of the plug may be held together by frictional contact between the except that the shell portion 23 is provided 55" adjacent its upper end with an inwardly projecting flange 40 which prevents longitudinal movement of the insulating block 29. and sleeve 27, but permits rotation of the yblock and sleeve to open' and close the apertures 25, and 27?. In Fig.3 the block 29 is secured directly to the shell portion 23 by spinning the-upper end of the shell porl- H tion over the projecting shoulder 30 of the block, 3nd a sleeve i-k rovided with the apertures 42 is frictionally mounted fiver the shell portion 23 In both of these forms means similar tothe tongue 52 and slot 50 may be provided. In Fig. 4 the upper end of the sleeve 23 is'threaded toengage the knurled nut 43, by means of which the block 29 is held in place and a collar 44 is-slidably mounted; on the outside of the sleeve 23", the width'of the collar being substantially half the distance between the nut portion 45 of the shell and the knurled nut 43. The apertures 25 in this form are opened and closed by sliding the collar 44 longitudinally of the plug.

Having thus described my invention, what I claim as new and desire to secure by Let-. ters Patent, is: l

1. A spark plug comprising a base, a top piece having a shell like casing, an insulating block and sleeve slidably carried by said casing for longitudinal or rotatable movement, an electrode carried by said base, a'

second electrode carried by said block and spaced from said first named electrode within said casing to provide an air ap, and said casing and sleeve provided wit a plurality of'apertures adapted to be moved into or out of registry by the rotatable movement of said sleeve.

2. A spark plug comprising a base, a top piece having a shell like casing, an insulating block and sleeve slidably carried by said casing for longitudinal or rotatable movement, an electrode carriedby said base, a second electrodecarried by said block and spaced from said first named electrode within said casing to provide an air gap, and said casing and sleeve provided with a plurality of apertures adapted to be moved into or out of registry by the rotatable movement of said sleeve and-means to retain said sleeve with said apertures in opened or closed positions.

3. A spark plug comprising abase, a top piece having a shell like casing, an insulating block and sleeve slidably carried by said casing for longitudinal or rotatable movement, an electrode carried by said base, a second electrode carried by said block and spaced from said first named electrode within said casing to provide an air gap, and said casing and sleeve provided with a plurality of apertures adapted to be moved into or out of registry by the rotatable movement of said sleeve and said sleeve adapted to increase said air gap and short circuit said plug when it is moved longitudinally.

4. A spark plug comprising a. base, a top piece having a shell like casing, an insulating'blockand sleeve slidably carried by said casing for longitudinal or rotatable movement, anelectrode carriedby said base, a second electrode carried by said block and spaced .irnzp said first named electrode within said casing to pro-ridden air gap,

and said casing and sleeve provided with a plurality of apertures adapted to be moved into or out of registry by the rotatable movement of said sleeve, said sleeve adapted to increase said air gap and short circuit said plug when it is moved longitudinally, and means to retain said sleeve with said normal operative position.

In testimony whereof I have affixed my signature.

EMIL GRAF. 

